Yes, don't read too much into her contacting more, b/c there are probably are legit reasons. You did not make a mistake by giving your W a compliment, and she obviously liked it. Don't misread how you saw her that day at school. She is excited in her new position and yet recognizing there has personal pain for you (maybe both of you). As a woman, that could explain a "sad" smile.
Don't take any of those things to be a "sign". Just take the good moments as they come, and to mean no more or no less. It is better to have a pleasant interaction than an ugly one, right?
I'm glad things are more peaceful. Sometimes a physical separation helps. And, yes, there have been couples to S and years later, R the M or get remarried.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!